Fair enough. So, let's go there. Presume that there is some sort of acceptable writeup for whatever flavor of mythical level character you'd like to see, and let's see the actual mechanics of that mythical character.
See, me? I'm a HUUUGE fan of exploding dice and lots of die rolling. My mythical warrior would get a power, somewhere in the high levels, where he just continues making attacks until he misses or there's nothing left to kill. You don't get X attacks per round. You get to attack until you miss or run out of targets. To me? That's a mythic level warrior. Maybe limit it to Proficiency bonus/day. I could live with that.
The warrior attacks spells that have concentration. The AC is equal to the casters Save DC. The attack deals no actual damage but triggers a Concentration check equal to either 10 or half the damage the warrior would have dealt on a hit, whichever is higher.
The warrior has a Proficiency Bonus number of times per day that he just succeeds on a check. If he wants to leap a chasm? He succeeds.
But, then again, I'm pretty simple. I'm sure others could come up with more interesting stuff.